Technical Field
Certain embodiments of the invention relate to the structure of a die lip driving unit.
Description of Related Art
In a lamination process for coating a base material such as a film, paper, or foil with a resin, a system which controls the thickness of the coating is known. In such a system, in order to control the flow rate of a molten resin which passes through an extruder, for example, a T-die is used. The T-die stores the molten resin in an internal manifold and distributes the molten resin in the width direction thereof such that the molten resin is derived into a sheet shape from the gap between a pair of lips provided at the tip end of the T-die.
The flow rate of the molten resin derived from the T-die is controlled by adjusting the size of the gap between the lips. Specifically, one of the pair of lips is referred to as a fixed lip, and the other is referred to as a flexible lip portion. The flexible lip portion is elastically deformed by driving an actuator such that the gap therebetween is adjusted.
In a configuration in the related art, a lever mechanism is disposed on the side surface of a die body, one end portion of the lever is connected to the flexible lip portion, and the other end portion is connected to the actuator. By driving the actuator and rotating the lever, the flexible lip portion is elastically deformed. In the lever mechanism, the driving force of the actuator is amplified by the principle of levers and is transmitted to the flexible lip portion. Therefore, control can be performed with good efficiency.